1. Field of the Invention
The present invention relates to mechanical attachments for front-end loaders and other similar vehicles. More particularly, the present invention relates to a grapple attachment comprising upper and lower jaws having a plurality of tines that are adapted for dislodging, lifting and carrying concrete slabs, logs, rocks and other debris.
2. Description of the Prior Art
It has become a standard to use front-end loaders in construction and agricultural operations. The typical front-end loader consists of a large bucket mounted on, and extending transversely to, the front of a tractor. The bucket can be used to collect and transport several different types of materials such as dirt, stones and loose material. Although bucket-style attachments assist in accomplishing a wide range of material handling tasks, their use is nevertheless limited. For example, such attachments can be awkward, if not completely ineffective, when the operator needs to lift and carry large objects such as brush, logs and large sections of concrete. Moreover, the design of the bucket-style of attachment is inefficient for piercing and breaking through solid ground cover commonly found in construction projects, including asphalt and concrete.
Several manufacturers in the art, such as John Deere and Kubota, have attempted to address these shortcomings by attaching grappling devices to front-end loader buckets. Such grapple systems typically include an upper, movable jaw member that pivots about a horizontal axis between open and closed positions relative to the fixed bucket. The movable jaw member opens and closes to secure the load within the mouth of the bucket. Once securely pinned within or against the opening of the bucket, the load may be lifted and carried to the desired location. This improvement helped to lift and carry some large and awkward materials with the bucket. However, both the buckets and the grappling arms created physical and visual obstructions to the desired operation of the attachment. Regardless of their position, the bucket and grapple devices commonly interfered with the operator""s view of the subject materials to be hauled and the bucket remained ineffective for piercing through solid ground cover.
Another shortcoming of the bucket-grapple attachment involves the limited linkage and actuation configuration of the jaw member. For example, there are certain orientations of the device which will render the actuating mechanism with a relatively short effective lever arm, providing little, if any, mechanical advantage. Accordingly, large actuators and heavy structural supports are frequently required to provide a broad range of grapple jaw movement.
A number of xe2x80x9cpure grapplexe2x80x9d attachments have been developed for unearthing, lifting and carrying large, awkward materials. U.S. Pat. No 6,098,320 teaches a grapple attachment comprising an upper jaw, having a plurality of grapples, that is pivotally mounted to the exterior of a tine frame which houses a plurality of elongated tines. The tine frame is connected to a mounting frame which is operatively coupled to the front of an end loader. The tines extend vertically through the tine frame so that they can be used to pierce the ground adjacent a partially buried rock. The upper jaw is pivoted toward and away from the tines by an actuator. This action enables the upper jaw and the tines to work together to extract the rock from the ground. However, while the fixed vertical position of the tines is helpful for piercing the ground cover, it is poorly suited for extending beneath planar and/or elongated materials such as concrete slabs or a plurality of logs. To lift and carry such materials, the attachment must rely on the pressure exerted by the upper jaw and actuator in pinning the materials between the upper jaw and the tines in an action not unlike a pair of tweezers. Thus, the attachment""s ability to lift and carry large planar objects is limited by the power of the actuator, the length of the grapples and tines and the size of the opening between the outward ends of the grapples and the tines. As any of these factors decreases, so does the lifting and carrying power of the grapple.
Other xe2x80x9cpure grapplesxe2x80x9d known in the art, which are better suited for lifting and carrying planar and/or elongated materials, teach the use of multiple actuators, pivot and extension arms or complex geometries and linkages. Such attachments are complex, expensive and difficult to manufacture. Accordingly, there is a need for an improved grapple attachment for front end loaders and other vehicles that is simple, but capable of piercing solid ground cover and hauling large, planar and/or elongated materials.
The present invention relates to a grapple attachment for front-end loaders and other vehicles. The grapple is comprised of upper and lower jaws, each having a plurality of elongated, generally angular tines. The upper and lower jaws are pivotally connected to each other at the rearward ends thereof and pivotally connected to the front-end loader. A single actuator moves the jaws between open and closed positions. A first end of the actuator is pivotally connected to the upper jaw and the second end of the actuator is operatively connected to the front-end loader and the operational controls thereof.
In operation, the grapple of the present invention is used to dislodge, lift and carry large planar and irregularly shaped materials. The grapple is particularly well suited for construction and agricultural operations ranging from the removal of brush and fallen trees to the dislodging, lifting and transporting of concrete slab. The lower jaw of the grapple is adapted to first pierce the concrete slab. The lower jaw can then be angled and driven beneath the concrete. The angular shape of the lower jaw allows it to place a substantial portion of its elongated upper surface closely adjacent the lower surface of the concrete. The actuator then closes the grapple so that the upper jaw engages the upper surface of the concrete. The front-end loader may then raise the grapple and transport the concrete slab to a desired location.
The grapple can be manufactured from high-tension steel for strength and durability. However, the simple geometry and construction of the grapple make it inexpensive and easy to manufacture. Its use of a standardized front-end loader hitch makes the grapple versatile for quick and easy assembly on a plurality of vehicle types.
It is therefore an object of the invention to provide an improved grapple attachment that is easy to manufacture and use on different types of front-end loaders and related vehicles.
A further object of the invention is to provide an improved grapple attachment having an upper jaw and a lower jaw that are pivotally connected to one another and capable of being pivoted in open and closed positions.
A further object of the invention is to provide an improved grapple attachment having an upper jaw and a lower jaw that are pivoted into open and closed engagement with one another by means of a single actuator.
A further object of the invention is to provide an improved grapple attachment capable of piercing solid ground cover and then lifting whole, planar sections thereof.
A further object of the invention is to provide an improved grapple attachment that is adapted to dislodge, lift and transport a plurality of materials such as brush, logs, rocks and slabs of concrete quickly and efficiently.
These and other objects of the present invention will be apparent to those skilled in the art.